An improvement on the digital redesign method using fuzzy PWM controller

In this paper, a new digital redesign composed of pulse width modulator (PWM) is proposed. The proposed PWM combines fuzzy logic with genetic algorithm (GA) to tune the parameter of the proposed controller such that the output response of hybrid system closely matches the one of original continuous system. Finally, an illustrated example is proposed to show the proposed method is superior to the existing one.     

A Study of a Robust Fuzzy Controller for Perturbed Nonlinear Systems

In this paper, a fuzzy logic controller (FLC) for a nonlinear system with uncertain perturbation is proposed. Based on the Lyapunov synthesis approach, we construct the FLC not only to stabilize the perturbed nonlinear system but also to guarantee a prescribed H_∞ norm bound of the closed-loop transfer function from the disturbance to the controlled output. A given example illustrates the availability of the proposed design method.     

Robust Output-Feedback Control for Linear Continuous Uncertain State Delayed Systems with Unknown Time Delay

The state-delayed time often is unknown and independent of other variables in most real physical systems. In this paper, a new stability criterion for uncertain systems with a state time-varying delay is proposed. Then, a robust observer-based control law based on this criterion is constructed via the sequential quadratic programming method. We also develop a separation property so that the state feedback control law and observer can be independently designed and maintain closed-loop system stability. An example illustrates the availability of the proposed design method.     

H∞ control via output feedback for linear systems with time-varying delays in state and control input

In this paper, an observer-based H_∞ controller for systems with time-varying delays in state and control input is proposed. Using the solution of proposed modified algebraic Riccati equation, we can construct a controller which depends on the maximum value of the time derivative of time-varying delay and guarantees a prescribed H_∞ norm bound of the closed-loop transfer matrix from the disturbance to the controlled output. A given example illustrates the availability of the proposed design method.     

Observer-Based H<Subscript>∞</Subscript> Controller for Perturbed System with State and Input Delay

This paper deals with the robust stability problem for continuous-time linear systems with external perturbation and time delay in state and control input. We derive a sufficient condition that guarantees the closed-loop delayed system stability and a prescribed H norm bound of the closed-loop transfer matrix from the disturbance to the controlled output. Based on this derivation, the proposed observer-based robust controller not only reduces the influence of the disturbance, but also guarantees the closed-loop system stability. An example is given to illustrate the availability of the proposed design method.